[PATCH-FOR-38] target: Fix READ_CAPACITY_16 regression

From: Nicholas A. Bellinger
Date: Wed Mar 02 2011 - 18:53:21 EST


From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

Hi James,

This patch fixes a regression for READ_CAPACITY to trigger SAI READ_CAPACITY_16 for
>= 0xffffffff virtual backends. This occured during v4.0.0-rc6 when the backend
read_capacity* handlers where moved into generic target_core_cdb.c code, and the
'unsigned long long blocks_long' piece was dropped from target_emulate_readcapacity().

This fix has been tested with TCM_Loop on .38-rc7 with lio-4.1 and is working as expected
with large block virtual backends:

[67826.897061] TARGET_CORE[loopback]->TPG[1]_LUN[0] - Adding READ-WRITE access for LUN in Demo Mode
[67826.897061] scsi 7:0:1:0: Direct-Access LIO-ORG FILEIO 4.0 PQ: 0 ANSI: 5
[67826.900933] sd 7:0:1:0: [sdd] 2621440000001 512-byte logical blocks: (1.34 PB/1.19 PiB)
[67826.901510] sd 7:0:1:0: [sdd] Write Protect is off
[67826.901684] sd 7:0:1:0: [sdd] Mode Sense: 2f 00 00 00

Please include into scsi-rc-fixes going to Linus for-38 mainline target code.

Reported-by: Ben Jarvis <bjarvismn@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_cdb.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/drivers/target/target_core_cdb.c b/drivers/target/target_core_cdb.c
index 366080b..7f19c8b 100644
--- a/drivers/target/target_core_cdb.c
+++ b/drivers/target/target_core_cdb.c
@@ -667,7 +667,13 @@ target_emulate_readcapacity(struct se_cmd *cmd)
{
struct se_device *dev = SE_DEV(cmd);
unsigned char *buf = cmd->t_task->t_task_buf;
- u32 blocks = dev->transport->get_blocks(dev);
+ unsigned long long blocks_long = dev->transport->get_blocks(dev);
+ u32 blocks;
+
+ if (blocks_long >= 0x00000000ffffffff)
+ blocks = 0xffffffff;
+ else
+ blocks = (u32)blocks_long;

buf[0] = (blocks >> 24) & 0xff;
buf[1] = (blocks >> 16) & 0xff;
--
1.5.6.5

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